Manhole liner and method of using the same

ABSTRACT

A manhole liner and a method of using the same are provided. The manhole liner is sized substantially equally to the largest diameter of the manhole, so that the liner does not have to stretch to be pressed against the manhole wall. Additionally, the liner is impregnated with a resinous material capable of curing and hardening. A bladder, preferably stretchable circumferentially and having a diameter less than the smallest diameter of the manhole, is inserted into the liner. The bladder is expanded to press the liner against the wall of the manhole to dispense resinous material from the liner, while the liner is able to fold over itself in areas having a diameter less than the original diameter of the liner. Because the bladder stretches to produce a smooth outside surface, the resinous material will migrate to areas in the folds and will cure with a smooth interior surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation of U.S. application Ser. No. 12/834,589, filedJul. 12, 2010, which application is hereby incorporated by reference inits entirety.

FIELD OF THE INVENTION

The present invention generally relates to a method and means ofrepairing a manhole. More particularly, but not exclusively, theinvention relates to a method and assembly for lining a manhole wall.

BACKGROUND OF THE INVENTION

Conventional manholes include a lower or bottom pad, a barrel having arelatively constant diameter adjacent the pad, a concentric or eccentriccone extending upwardly from the barrel, one or more adjusting rings toadjust the overall height of the manhole, and a casting frame on top ofthe adjusting rings to support a lid at an elevation substantially levelwith the surrounding pavement. The casting frame is preferably sealed tothe uppermost adjusting ring to preclude or minimize water flow into themanhole.

One problem with existing manholes is that many were made long ago, andthen oftentimes were made of brick. Due to the old age of the manholes,as well as the materials used to make them, many manholes have begun todeteriorate or have damaged areas. The damaged areas create weak spots,which may allow water to infiltrate the sewer system and also lead tothe eventual collapse of the manhole.

Methods exist for repairing the walls of manholes. One such methodinvolves the use of a cured-in-place (CIP) liner with a polymer coatingon its interior surface and a bladder to repair the manhole wall. Theliner and bladder are placed in the manhole, and the bladder is expandedto press the liner against the manhole wall. The liner is impregnatedwith a resin and applied to the wall to create a new interior wall ofthe manhole. One problem with existing methods is the size of the linerused to line the wall of the manhole. The methods call for the use of aCIP liner and bladder having a diameter approximately equal to thesmallest diameter of the manhole, with the liner being capable ofstretching circumferentially to press against the manhole wall so toprevent the liner from wrinkling. However, some manholes require thatthe liner stretch up to and exceeding 150% of its unstretched diameter.This can cause the liners to rip, tear or be too thin, leaving themanhole wall not fully repaired.

Additionally, because the liners include an interior coating imperviousto a resinous material, the liners cannot fold over themselves or bunchup because the liner wall would be formed with intermediate layers ofmaterial impervious to resin causing the liner to not be homogeneousacross its thickness.

Accordingly, there is a need in the art for an improved method and meansthat overcomes the problem of a liner tearing while stretchingcircumferentially to press against the wall of a manhole.

BRIEF SUMMARY OF THE INVENTION

It is therefore a principal object, feature, or advantage of the presentinvention to provide an improved method and means for lining a manholewhich improves over or solves the deficiencies in the art.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole wall thatallows a liner to fold over itself and to bunch up while still producinga smooth interior wall.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole wall whereinthe diameter of the liner is sized to be larger than the smallestdiameter of the manhole.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole wall whereinthe diameter of the liner is sized to be substantially equal to alargest diameter of the manhole.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole that uses aliner to transport a resinous material capable of curing and hardeninginto a manhole.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole that uses abladder capable of stretching circumferentially to press the lineragainst the wall of the manhole.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole that uses aliner for containing a resinous material capable of curing andhardening.

Another object, feature, or advantage of the present invention is toprovide an improved method and means for lining a manhole that can beused in manholes having varying diameters along the height of themanhole.

These and/or other objects, features, and advantages of the presentinvention will be apparent to those skilled in the art. The presentinvention is not to be limited to or by these objects, features andadvantages, and no single embodiment need exhibit every object, feature,and advantage.

According to one aspect of the present invention, a method of lining amanhole having varying diameters along its height is provided. Themethod includes taking a manhole liner having a tubular shape and anunstretched diameter larger than a smallest diameter of the manhole. Theliner is impregnated with a resinous material capable of curing andhardening. The liner is positioned in the manhole, and a bladder isinserted into the liner. The bladder is then expanded to press the lineragainst the wall of the manhole, with the liner folding on itself alonga portion of the liner. The resinous material is allowed to cure andharden to produce a smooth finished surface, including along the portionof the liner folded on itself. Finally, the bladder is removed from themanhole.

According to another aspect of the present invention, a method of lininga manhole having varying diameters along the height of the manhole andhaving a largest diameter near the bottom of the manhole and a smallestdiameter near the top of the manhole is provided. The method includestaking a manhole liner having a diameter substantially equal to thelargest diameter of the manhole. The liner is impregnated with aresinous material capable of curing and hardening, and then positionedin the manhole. An inflatable bladder capable of stretchingcircumferentially is inserted into the liner. Next, the bladder isinflated to circumferentially stretch the bladder to press the manholeliner into contact with the wall of the manhole. The liner is foldedover itself along an upper portion of the manhole. The resinous materialis allowed to cure and harden against a substantially smooth surface ofthe bladder, and then the bladder is removed from the manhole.

According to yet another aspect of the present invention, a linerassembly for lining a manhole having varying diameters along the heightof the manhole, with the largest diameter near the bottom of the manholeand the smallest diameter near the top of the manhole, is provided. Theliner assembly includes a bladder and a manhole liner. The bladdercomprises a first end, and opposite second end, and a bladder body therebetween, wherein the bladder body has a diameter smaller than or equalto the smallest diameter of the manhole. The bladder is also capable ofstretching circumferentially. The manhole liner comprises a manholeliner body along its height, with the manhole liner body having adiameter substantially equal to the largest diameter of the manhole.Additionally, the manhole liner is impregnated with a resinous materialcapable of curing and hardening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an exemplary structure of a manhole.

FIG. 2 is a sectional view of the liner assembly of the presentinvention positioned in a manhole.

FIG. 3 is a top sectional view of the manhole of FIG. 2 according toline 3-3 of FIG. 2.

FIG. 4 is a view similar to FIG. 2 showing the bladder fully inflated inthe manhole.

FIG. 5 is a sectional view according to line 5-5 of FIG. 4.

FIG. 6 is a sectional view of the repaired manhole after the bladder hasbeen removed.

FIG. 7 is a sectional view according to line 7-7 of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a sectional view of an exemplary structure of a manhole 10.The manhole 10 includes a bottom floor 12, a barrel 16 above the bottomfloor 12, a cone 18 supported by the barrel 16, and a plurality ofadjusting rings 20 supported by the cone 18. A casting frame 22 residesupon the upper most ring 20 and supports a lid 26. The casting 22 isnormally sealed to the top ring 20. It is understood that one or morerings 20 may be used to adjust the height of the manhole 10 such thatthe lid 26 is substantially at the level of the pavement 66 surroundingthe manhole 10. Also, while FIG. 1 shows the cone 18 to have aconcentric shape, it is understood that an eccentric cone can beutilized such that the manhole 10 has an asymmetrical cross-sectionalappearance. FIG. 1 also shows an optional run through 14 in the bottomfloor 12. While each manhole generally has unique size and shape, it isgenerally understood that the basic construction of the manhole 10 issimilar in all manholes. Although manholes comprise varying diametersD1, D2, D3, and D4 along the height of the manholes, the manholesgenerally are narrower at the top section, or chimney, than at thebottom section. Additionally, bricks 72 generally form the wall 24 ofmanholes.

FIG. 2 is a sectional view of the liner assembly 30 of the presentinvention positioned in a manhole 10. The liner assembly 30 includes abladder 32, a manhole liner 42, and a base 68. The bladder 32 comprisesa first end 34 attached to the base 68 near the opening 28 of themanhole 10, a second end 36 positioned at the bottom 58 of the manhole,and a bladder body 38 there between. The first end 34 of the bladder 32may be attached to the base 68 outside of the manhole 10 as well. Thediameter 40 of the bladder 32 is preferably less than or equal to thesmallest diameter D1 of the manhole 10. However, the bladder body 38 isstretchable such that it is able to press against a wall 24 of themanhole 10 when expanded. The manhole liner 42 is attached at theopening 28 of the manhole, and comprises a manhole liner body 44 that atleast partially surrounds the bladder body 38 in the manhole 10. Themanhole liner body 44 is comprised of lining material substantially freeof coating or intermediate layers of material impervious to the resinousmaterial 48. The resinous material 48 may be a thermoset resin, whichsaturates the liner and cures and hardens quicker in the presence ofheat. However, it should be appreciated that other resinous materialsmay be used, on the condition that they are able to cure and harden. Themanhole liner 42 is essentially a transport device, such that theresinous material 48 forms the structural properties of the liner whencured.

The diameter 46 of the manhole liner 42 in one preferred form is sizedsubstantially equal to the largest diameter D1 of the manhole 10.Therefore, the manhole liner 42 does not need to be stretchable. Afterthe manhole liner 42 has been impregnated with a resinous material 48,the manhole liner 42 is positioned in the manhole 10. The bladder 32 isthen inserted into the manhole liner 42. FIG. 3 is a top sectional viewof the manhole 10 of FIG. 2 according to line 3-3 of FIG. 2. FIG. 3shows the bladder 32 and the manhole liner 42 positioned in the manhole10. As is seen in FIG. 3, the diameter 40 of the bladder 32 is less thanthe diameter 46 of the manhole liner 42. As is also shown in FIG. 3, theoriginal diameter 46 of the manhole liner 42 is substantially greaterthan the diameter D3 of the manhole 10 at the adjusting rings 20.Because the diameter 46 of the manhole liner 42 is greater than thediameter D3 of the adjusting rings 20, the manhole liner will fold overitself and bunch up to fit within the top section 60 of the manhole 10.

In another preferred form, the diameter 46 of the manhole liner 42 issized larger than the smallest diameter of the manhole 10. Here, themanhole liner will again fold over on itself and bunch up to fit thesmaller diameter portions of the manhole 10.

FIG. 4 is a sectional view similar to FIG. 2 showing bladder 32 fullyinflated in the manhole 10. The bladder 32 is inflated with fluidpressure (not shown), such as air, introduced to the cavity 70 of thebladder body 38. The increased pressure causes the stretchable bladderbody 38 to expand circumferentially towards the wall 24 of the manhole10. The expanded bladder will press the manhole liner 42 against thewall 24 of the manhole 10. This will create a layer 64 of resinousmaterial 48 between the manhole liner 42 and the bladder body 38.Because the bladder 32 has stretched circumferentially against themanhole liner 32, the bladder body 38 will have a smooth surfaceabutting the layer 64 of resinous material 48. This ensures that theresulting manhole wall 24 will be smooth.

FIG. 5 shows a top sectional view of the manhole 10 of FIG. 4 accordingto the line 5-5 of FIG. 4. FIG. 5 is a sectional view of the manhole 10near the top section 60 of the manhole 10, where the diameter D3 of themanhole is substantially smaller than the diameter D1 of the bottom 58of the manhole 10. Because the manhole liner 42 has been sizedsubstantially equal to the diameter D1 of the larger section of themanhole 10, there will be excess manhole liner body 44 at this uppersection. The excess manhole liner body 44 will fold over itself andbunch up to create folds 52 in the liner. However, because the manholeliner 42 does not contain a resin impermeable coating, the folds 52 willcompress and resinous material 48 will form a manhole liner 42 in thesame way as in the bottom section, where the manhole liner 42 is asingle layer. The compression creates a layer 62 of resinous material 48between the manhole liner 42 and the bladder 32. The thickness of thelayer 62 of resinous material may vary according to the number of folds52 or bunches in the manhole liner 42. However, because the bladder 32was stretched to press the manhole liner 42 against the wall 24 of themanhole 10, the bladder 32 will have a smooth surface 56 pressed againstthe varying layers of resinous material 48. This will result in theresinous material having a smooth interior surface. Because the folds 52contain two or more layers of manhole liner 42, the resinous material 48will cure and harden to produce a thicker wall 24 of the manhole 10 atthe top section 60 of the manhole. However, because the top section 60,including the cone 18 and adjusting rings 20 (the chimney), of themanhole 10 undergoes the most stress and usually contains the mostdamage, the resulting thicker wall 24 will be stronger to help resistcracking due to freezing and thawing.

FIG. 6 is a sectional view of the manhole 10 after the resinous material48 has cured and hardened and the bladder 32 has been removed from themanhole 10. The bladder 32 may be removed by deflating the fluid fromthe cavity 70, and then by pulling a rope (not shown) connected to thesecond end 36 of the bladder 32. Pulling the bladder 32 out by thebottom first causes the bladder 32 to peel away from the cured resinousmaterial 48. Although peeling the bladder 32 requires the least amountof effort, it should be appreciated that the bladder 32 may also bepulled straight out of the manhole 10 from the first end 34 of thebladder 32 as well. After the manhole lid 26 is replaced on the castingframe 22 of the manhole, what remains is a manhole 10 having a repairedand structurally renewed wall 24. As is shown in FIG. 6, the manholeliner 42 has compressed the impregnated resinous material 48 from themanhole liner body 44, creating a cured resinous material layer 62around the interior periphery of the manhole 10. As stated above, thelayer 62 will be thicker in the top portion 60, or the chimney, of themanhole 10 because the manhole liner will have folded over itself. Thethicker layer aids the section most affected by the elements, however.The folds 52 will occur in areas of the manhole 10 having a diameterless than the largest diameter D1 of the manhole 10.

FIG. 7 is a top sectional view of the manhole 10 of FIG. 6 according tothe line 7-7 of FIG. 6. FIG. 7 shows that although the manhole liner 42folded over itself, the manhole liner 42 was compressed against thesmooth outer surface 56 of the bladder 32, such that the interiorperiphery of the resinous material 48 cured into a smooth finish 50. Atthe upper section of the manhole, the folds 52 of the manhole liner 42will cause the cured resinous layer 62 to be thicker than at the bottomof the manhole 10. However, because the bladder 32 is pressed againstthe manhole liner 42 with even pressure, the layer 62 of resinousmaterial 48 will be substantially equal at a given height around theinterior of the manhole 10. The resinous material 48 will migrate fromthe liner to fill low areas of the liner, formed due to the folds, tocreate a resinous surface that is smooth about the interior periphery ofthe manhole 10. The smooth finish 50 of the cured resinous material 48allows the manhole to be used as it had previously before it requiredrepair.

The invention has been shown and described above with reference topreferred embodiments, and it is understood that modifications,substitutions, and additions may be made which are within the intendedspirit and scope of the invention. The invention is only to be limitedby claims appended hereto.

What is claimed is:
 1. A method of lining a manhole having varyingdiameters along its height, comprising: taking a manhole liner having atubular shape and an unstretched diameter at least partially larger thana smallest diameter of the manhole; impregnating the liner with aresinous material capable of curing and hardening; positioning the linerin the manhole; inserting a bladder into the liner; expanding thebladder to press the liner against the wall of the manhole; wherein theliner can fold over on itself along at least a portion of the liner;allowing the resinous material to cure and harden to produce a smoothfinished surface, including along the portion of the liner folded onitself; and removing the bladder from the manhole.
 2. The method ofclaim 1 wherein the liner will fold on itself at narrower diameters ofthe manhole along the height of the manhole.
 3. The method of claim 2wherein the liner will not fold on itself at a portion of the manholehaving a largest diameter.
 4. The method of claim 1 further comprisingallowing the resinous material to migrate to locations in folds of theliner to produce a smooth surface on the liner.
 5. The method of claim 1wherein the bladder is smaller or equal to a smallest diameter of themanhole.
 6. The method of claim 1 wherein the bladder is expanded byinflating the bladder by applying a fluid pressure within the bladder.7. The method of claim 6 wherein the bladder is capable of stretchingcircumferentially to press the liner against the wall of the manhole. 8.The method of claim 7 wherein the bladder comprises a first end, anopposite second end, and a bladder body there between.
 9. The method ofclaim 8 wherein the bladder body is a smooth surface when the bladderhas been inflated and stretched circumferentially.
 10. The method ofclaim 1 wherein the manhole liner is seamless in construction.
 11. Amethod of lining a manhole having varying diameters along the height ofthe manhole, comprising: taking a manhole liner having a diametersubstantially equal to a largest diameter of the manhole; impregnatingthe liner with a resinous material capable of curing and hardening;positioning the liner in the manhole; inserting an inflatable bladdercapable of stretching circumferentially into the liner; inflating thebladder to press the manhole liner into contact with a wall of themanhole; wherein the liner folds over itself along at least a portion ofthe wall of the manhole wherein the diameter of the liner is greaterthan the diameter of the manhole; allowing the resinous material to cureand harden against a substantially smooth surface of the bladder; andremoving the bladder from the manhole.
 12. The method of claim 11further comprising pressing the liner against the manhole wall to causethe resinous material to migrate from the liner to areas in the linerfolds so to form a smooth resinous interior surface.
 13. The method ofclaim 12 wherein the resinous material cures and hardens to produce asmooth finished surface.
 14. The method of claim 11 wherein the bladderis inflated with a fluid pressure.
 15. The method of claim 14 whereinthe resinous material is a thermoset resin.
 16. The method of claim 15wherein a heated fluid is used to inflate the bladder to increase therate of curing and hardening of the thermoset resin.
 17. The method ofclaim 11 wherein the manhole liner does not stretch circumferentially.18. The method of claim 17 wherein the manhole liner will not fold overitself at the largest diameter of the manhole.
 19. The method of claim11 wherein the bladder diameter is equal to or smaller than a smallestdiameter of the manhole.
 20. A liner assembly for lining a manholehaving varying diameters along the height of the manhole, with thelargest diameter toward the bottom of the manhole and the smallestdiameter toward the top of the manhole, comprising: a bladder having afirst end, an opposite second end, and a bladder body there between,wherein the bladder body has a diameter smaller than or equal to thesmallest diameter of the manhole; wherein the bladder body is capable ofstretching circumferentially; a manhole liner having a manhole linerbody along its height, the manhole liner body having a diametersubstantially larger than the smallest diameter of the manhole; andwherein the manhole liner is impregnated with a resinous materialcapable of curing and hardening; and wherein the manhole liner capableof folding on itself at a location of the manhole wherein the manholeliner has a diameter greater than the manhole such that the liner willstill produce a smooth finished repair surface.
 21. The liner assemblyof claim 20 wherein the manhole liner is tubular shaped.
 22. The linerassembly of claim 20 wherein the manhole liner is a seamlessconstruction.